Structural diversity.
Ugander et al. are the first to propose the concept of structural diversity [1]}, which is further applied for influence analysis [2]}, [3]}, [4]}, [5]}. Specifically, given a friendship \((v_s,v_t)\in \mathcal {E} \) , the \({\mathtt {TFC}}\)  measure based on the structural diversity equals to the number of weakly connected components (see Definition REF ) in a subgraph, which is derived from \(v_t\) 's source neighbors affected by a specific event and their relationships. This work [1]} points out that a more extensive structural diversity of \(v_t\)  indicates a higher probability that \(v_t\)  will be influenced.
[Weakly Connected Component]
Given a directed graph, a weakly connected component is a maximal subgraph, where any inside node is connected by paths if ignoring the direction of edges.
